feat(uat-b1): ship Wave A-E of Bucket 1 audit findings

Wave A (Interest+EOI form quick wins):
- Auto-select yacht after inline-create from interest form
- EOI generate dialog: "View EOI" action toast
- Interest form berth picker: formatBerthRange compact label
- Remove "Generate EOI" button from Documents tab (clean removal)
- Interest auto-assign: only sales_agent/sales_manager auto-claim
  ownership on create (explicit role check via user_port_roles join)
- LinkedBerthRowItem dims: drop "D" suffix + "L × W" format
- ExternalEoiUploadDialog: prefillSignatories prop threaded from
  active EOI signers
- EOI signature progress on Overview milestone card footer

Wave B (a11y + i18n sweeps):
- aria-live on supplemental-info error state
- text-[10px] -> text-xs in client-pipeline-summary
- Currency formatter: locale default removed (Intl uses runtime)
- en-US/en-GB hardcoded toLocaleString swept across 13 components

Wave C (Primary berth always in EOI bundle):
- Service guard strengthened on update path
- Migration 0083 backfills historical primary rows

Wave D (Onboarding super_admin discoverability):
- /api/v1/admin/onboarding/status endpoint + shared service
- Topbar OnboardingBanner (super_admin, session-dismissible)
- OnboardingTile dashboard widget (rail group, self-hides at 100%)
- Celebration toast + invalidate of shared status on last tick

Wave E (Branded post-completion email idempotency):
- Verified handleDocumentCompleted already owns the email fan-out
- Added regression test for the polling path + idempotency

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/dashboard/widget-registry.tsx

@@ -15,6 +15,7 @@ import dynamic from 'next/dynamic';
 
 import { ActiveDealsTile } from './active-deals-tile';
 import { ActivityFeed } from './activity-feed';
+import { OnboardingTile } from './onboarding-tile';
 import { BerthHeatWidget } from './berth-heat-widget';
 import { ClientsByCountryWidget } from './clients-by-country-widget';
 import { HotDealsCard } from './hot-deals-card';
@@ -105,6 +106,19 @@ export interface DashboardWidget {
 }
 
 export const DASHBOARD_WIDGETS: readonly DashboardWidget[] = [
+  // ── Onboarding (rail, super_admin-only) ─────────────────────────────
+  // Self-collapses when the checklist hits 100% and self-hides for
+  // non-super-admin users so most reps never see this tile at all.
+  {
+    id: 'onboarding_checklist',
+    label: 'Setup checklist',
+    description:
+      'Progress + next-step nudge while the org is still going through Documenso / branding / users setup. Hidden once 100% complete.',
+    render: () => <OnboardingTile />,
+    group: 'rail',
+    defaultVisible: true,
+  },
+
   // ── KPI tiles (rail) ────────────────────────────────────────────────
   // Off by default - keep the existing dashboard layout unchanged for
   // users on first paint after the upgrade; reps can flip them on from